In the conventional art, since a Zernike/Pseudo-Zernike moment includes an orthogonal basis function, it shows the characteristics of an image more efficiently than a geometric moment, Legendre moment, rotational moment and the like. On the contrary, a method for extracting a Zernike/Pseudo-Zernike moment has the following problem.
The method for extracting a Zernike/Pseudo-Zernike moment according to the conventional art includes the method for storing the result of repeated calculations on a look-up table and using the stored result in extracting a moment.
However, the above method used in extracting a moment requires much moment extraction time, and a large amount of memory utilization necessary for memory extraction is needed in order to store the look-up table.
On the other hand, another conventional method includes an approximation method for approximating a Zernike/Pseudo-Zernike moment basis function in a square shape.
However, the above method has a problem that it is impossible to extract an accurate moment for an image, though a moment extraction speed can be increased.